This is the second phase of a three-phase prospective longitudinal study of 250 6- through 10-year-old disruptive and/or depressive boys. The general aims of the study are: to extend a two-factor model of child disruptive psychopathology to a third factor of depression or emotionality; to externally validate that extended three-factor model, using convergently and divergently valid direct measures of the three factors (i.e., inattention-overactivity, aggression, and emotionality); to compare the extended three-factor model to several stages of the DSM and Achenbach assessment models; to improve understanding of comorbidity within and between the disruptive and depressive disorders; to develop and test methods for combining, assessment data from different instruments and informants into sound diagnostic decisions; and to make a consolidated empirically-derived proposal for subgrouping the disruptive and depressive disorders/dimensions. Considered categorically, there are eight subgroups of referred boys: (1) exclusively hyperactive = H; (2) exclusively aggressive = A; (3) exclusively emotional = E; (4) combined hyperactive and aggressive = HA; (5) combined hyperactive and emotional = HE; (6) combined aggressive and emotional = AE; (7) mixed hyperactive and aggressive and emotional = HAE; and (8) neither hyperactive nor aggressive nor emotional = psychiatric controls or PC, as well as 200 classmate comparison boys or CC, and 80 full brothers. The dependent criteria for external validation include: symptom expression variables (e.g., duration, severity, and pervasiveness); impairment variables (academic problems, friendships, treatments); family context variables (e.g., family composition, parenting styles, marital harmony); cognitive and laboratory measures (e.g., intellectual functioning, academic skills, CPT); observational measures (e.g., behavior in play and task settings, parent-child interactions); generation indices (i.e., child and adult dimensions and disorders in parents); course of symptoms (psychiatric symptoms/behavioral dimensions assessed at average ages of 8, 12, and 15); and diagnostic outcomes (assessment and prediction of psychiatric disorders/ behavioral dimensions at age 15). This second phase of the investigation will complete follow-up of 250 probands between ages 11 and 13; and it will incorporate a sibling comparison component, using information about the 6- through 10-year-old and the 11-through 13-year-old sisters and brothers of the referred boys to answer more fully questions about the expression, diagnosis, and development of disruptive and depressive dimensions/disorders in boys and girls.